1. Field of the Invention
The present invention relates to a broadcast receiver for receiving a broadcasting of a predetermined channel transmitted from a broadcasting station by using a directivity switching antenna.
2. Description of the Related Art
In the USA, etc., an individual ordinary home is usually surrounded by a plurality of interspersed broadcasting stations (or base stations). In order to make reception of broadcasts from all of such broadcasting stations possible under such circumstances, it has been proposed to control directivity of an antenna by providing a plurality of antenna elements on the antenna and changing amplitude and phase of radio wave to be received by the antenna elements (for example, JP-A-11-298226 (paragraphs 0008 to 0010)). In JP-A-11-298226, when a channel of a TV receiver is switched to another, the directivity of antenna is scanned omnidirectionally from 0° to 360° to search a directivity direction of the antenna in which maximum receiving power level is obtained. When such directivity direction is obtained, the directivity of the antenna is controlled such that the directivity of the antenna is fixed to the directivity direction thus obtained.
On the other hand, in a radio LAN (Local Area Network) system, in which data and sound, etc., are sent and received, it has been proposed to provide a smart antenna having a directivity capable of being switched on a device such as a personal computer (for example, JP-A-2004-15800 (paragraphs 0043 to 0119 and FIG. 2)). In JP-A-2004-15800, parameters of the smart antenna are stored in a memory of the device as information for keeping the receiving characteristics such as receiving signal intensity and bit error rate of the receiving signal in an acceptable state. In starting a communication, the parameters stored in the memory are set in the smart antenna and the communication is performed. During the communication, the device monitors the receiving characteristics and, when it is detected that the receiving characteristics become lower than a reference value of performance, the smart antenna is scanned to search a direction in which the receiving characteristics become better. The directivity of the smart antenna is kept to the better direction and parameters with which the better direction is obtained are stored in the memory.